Wide‐angle reflectivity across the Torngat Orogen, NE Canada

Abstract

Data from a Lithoprobe refraction/wide‐angle reflection seismic transect across the Torngat Orogen in NE Canada were depth‐migrated to produce a record section similar to near‐vertical incidence seismic data. Densely spaced airgun shots and a station spacing between 9 and 25 km were able to produce a low‐frequency image of the lower crustal reflectivity for most of the transect. Over the western end of the profile, a series of east‐dipping lower crustal reflectors continue down to the Moho, which is clearly defined at a depth of 36 to 38 km. The lower crustal reflectors can be correlated laterally for up to 80 km. This reflection fabric is interpreted as evidence for thick‐skinned deformation caused by convergence of the Nain and Superior provinces. Over the eastern end of the line, reflectors in the Nain Province are less continuous and may indicate steeply dipping faults, which have not been modified during formation of the orogen.